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Nathan Wood, chair of BESA’s Health & Wellbeing in Buildings group looks at the debate about air quality in our schools.

The planned full reopening of schools in England has reignited the debate about how best to minimise the risk of virus transmission among pupils and teachers – and must surely prompt a fresh look at ventilation?

Decades of under-investment in school buildings has been brought sharply into focus by the pandemic.

School managers had very few weapons at their disposal with which to fight the virus and what budget they did have was largely used up on social distancing signage, improving handwashing facilities, boxes of tissues and PPE.

When it became apparent that the virus was airborne, most had no adequate mechanical ventilation and reverted to opening windows to try and increase airflows.

Now that schools are preparing to re-open on March 8, they are at least armed with greater knowledge about how the virus moves around indoor spaces, but few have the means to act on that knowledge.

You’ll also be watching your energy bills soar and carbon footprint grow as expensively generated heat flies out the window.

NathanWood BESA Nathan Wood Chair of the BESA Health & Wellbeing in Buildings group


In fact, many can’t even open all their windows, and most urban schools should not because of their location next to busy roads making them vulnerable to air pollution and noise.

The national media usually turns to architects when addressing any building-related issue, but they are not the profession charged with making buildings work, live and, in effect, breathe.

That is the responsibility of engineers.

Architects tend to focus on the aesthetics and how the spaces work. This gives them an affinity to natural ventilation, which they also champion as part of the net zero carbon agenda.

However, if you are forced to open windows during the colder months – not only will you be raising the chances of children becoming hypothermic, but you will also be watching your energy bills soar and carbon footprint grow as expensively generated heat flies out.

In any case, opening windows does not guarantee the air change rates needed to reduce viral loads.

It is completely temperature and wind direction dependent and likely to leave unventilated, stagnant spots around the room. That freezing child next to the window might be virus free, however!

The link between health and air quality

The BESA Health & Wellbeing in Buildings (H&WB) group recently welcomed Rosamund Adoo Kissi-Debrah as its honourary president.

She is a larger than life, powerful driver for change and, in her role as the UK’s first World Health Organisation (WHO) advocate for health and air quality, is generating impressive momentum behind our work to clean up the indoor air of thousands of buildings across the UK.

She reminds us that this is very far from being simply a technical issue. It is all about social justice and the human right of people to breathe clean air and live and work in a built environment that supports their hopes and helps them raise their families.

“While we will continue the fight for local and central government to take proper measures to reduce air pollution in our cities; we will also push building owners and operators to look at how they can make their buildings cleaner and safer for us and our children,” Ros told last year’s BESA Conference.

“We have come to expect buildings to be able to keep us cooler on hot days and warmer on cold ones; so why should we not also expect them to be able to provide a clean air environment when pollution is rising outside?”

Creating safe havens

This places responsibility on our industry to design buildings as ‘safe havens’ where people can live, work, play…and learn safely.

One of the UK’s top experts on building ventilation is also a member of the government’s scientific advisory group SAGE. Professor Cath Noakes has been a vocal proponent of “engineered solutions” to the indoor air quality (IAQ) challenge and has clearly set out the gaps in the current strategy that relies on natural ventilation.

She has been telling the government that engineering controls should sit above measures that rely on human behaviour such as distancing and wearing face coverings in any “hierarchy of risk control”.

“We don’t have all the answers, but we do know we need to ventilate better,” she told a recent BESA webinar.

“This is not just about flow rates as it depends on the size of the space. 10 litres per second per person is the ideal, but if people are close together and for an extended period, we may need more flow rate. You can also have quite a lot of people in a large space with lower ventilation rates.”


“The spaces that worry me the most are those that are naturally ventilated as these are temperature and wind dependent…they often rely on opening doors as well,” said Noakes, who is professor of Environmental Engineering for Buildings at the University of Leeds and has also been providing advice on airborne transmission to the NHS during the pandemic.

The key factor with an engineered mechanical ventilation approach is that it can give the end user control over the air movement.

The paths taken by air is critical and will be different depending on the layout of the space and the occupancy levels.  

Ventilation manufacturers and specialist contractors are working on low cost engineered solutions that are long overdue but have not yet been produced on any great scale for schools because of low demand (no budget).

Free guide

Before the pandemic, local authorities were facing growing community pressure to address the air quality issues around school buildings caused by traffic pollution.

Now, in the wake of Covid-19, the focus has moved inside and, if we want people to feel more confident about returning to any communal building, then this issue needs to be properly addressed.

A good starting point for anyone struggling to get to grips with the IAQ in their building is the new ‘Beginner’s Guide to IAQ’ jointly produced by BESA and Mitsubishi Electric. It offers advice and guidance for employees and visitors to commercial buildings and, with so many people now working from home, includes some easy tips for optimising IAQ in residential settings.

Nathan Wood is managing director of Farmwood M&E. He is also leading a project on behalf of BESA to develop low cost indoor air quality solutions that can be implemented by ALL schools.